#153. Find Minimum in Rotated Sorted Array

Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.
(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).
Find the minimum element.
You may assume no duplicate exists in the array.

Python

# Time O(n)
# Space O(1)
# Method : direct search

class Solution(object):
    def findMin(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        min = nums[0]
        for i in range(len(nums)):
            if nums[i] < min:
                min = nums[i]
        return min

# Time O(log(n))
# Space O(1)
# Method : Binary search


class Solution(object):
    def findMin(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        left = 0
        right = len(nums) - 1
        while left <= right:
            mid = (left + right) / 2
            if nums[mid] < nums[right]:
                right = mid
            else:
                left = mid + 1
    # 最后一次 left==right，此时，mid即为所求，当仍进入循环；
    # 此时，a[mid]==a[right]，导致left多加了1
        return nums[left - 1]

223195530704881162.jpg

C++

class Solution {
public:
    int findMin(vector& nums) {
        int min = nums[0];
        int L = nums.size();
        for(int i=0;i